{'create': datetime.datetime(2011, 1, 3, 12, 38, 38, 202672), 'author': 'vvs'}
{'create': datetime.datetime(2011, 1, 3, 12, 38, 38, 203375), 'author': 'vvs'}
Traceback (most recent call last):
  File "/home/vvs/Programming/dimcalc/dimcalc.py", line 542, in <module>
    dimcalc = DimCalc()
  File "/home/vvs/Programming/dimcalc/dimcalc.py", line 222, in __init__
    self.series_to_store()
  File "/home/vvs/Programming/dimcalc/dimcalc.py", line 280, in series_to_store
    str(series), ''])
  File "/home/vvs/Programming/dimcalc/dimension.py", line 45, in __str__
    mystr(self.__un_tolerance, True, True)+')'
TypeError: cannot concatenate 'str' and 'NoneType' objects
